Electronic device and method in an electronic device for processing image data

ABSTRACT

The invention relates to an electronic device for performing imaging, including a camera means for creating image data (ID) from an imaging target (IT), the imaging target (IT) including at least one primary image object (I 1 ) and at least one secondary image object (I 2 ), an image-processing chain arranged in connection with the camera, for processing the image data created from the imaging target, and a focussing unit for focussing the camera on at least the primary image object. In addition, a blurring unit is arranged in the image-processing chain, to blur at least some of the said secondary image objects in the image data, and arranged to use the information produced by the focussing unit.

TECHNICAL FIELD

The present invention relates to an electronic device for performingimaging, including

-   -   camera means for forming image data from an imaging target, the        imaging target including at least one primary image object and        at least one secondary image object,    -   an image-processing chain arranged in connection with the camera        means, for processing the image data formed from the imaging        target, and    -   focussing means for focussing the camera means on at least one        primary image object.

In addition, the invention also relates to a corresponding method,program product, and focussing module, for implementing the invention.

BACKGROUND

In small digital cameras, the depth of field is relatively wide, due to,among other factors, their short focal length. One example of this groupof cameras is mobile stations equipped with a digital imagingcapability. The great depth of field makes it difficult to create ablurred background in the image. One example of such an imagingapplication is portraits. In them, it is only the primary image objectthat is desired to be shown sharply, the background, i.e. the secondaryimage objects, being desired to be blurred.

Solutions are known from the prior art, in which a shallow depth offield is implemented by using a large aperture (small F-number) and along focal length. This arrangement is known, for example, from SLR(Single Lens Reflex) cameras. Another possibility is blurringimplemented by post-editing. This is a common functionality, forexample, in still-image editors.

U.S. patent publication US-2002/0191100 A1 (Casio Computer Co. Ltd.)discloses one background-blurring method performed in a camera device inconnection with imaging. It is based on capturing two images at themoment of imaging. The first image is focussed on the primary imageobject and before the second image is captured the focussing is alteredto either the close or distant setting. After taking the shots, thefirst and second images are synthesized with each other. As a result ofthe synthesizing, a final image is obtained, in which the object isimaged sharply while the background is blurred.

Some other prior arts applying two or several images describe US2002/0140823 A1, US 2002/0060739 A1, US 2003/0071905 A1 and US2002/0191100 A1.

SUMMARY

The present invention is intended to create a way of blurringnon-desired imaging objects in digital imaging. The characteristicfeatures of the electronic device according to an embodiment of theinvention include the following. For example, an electronic device forperforming imaging, includes a camera means for forming image data froman imaging target, the imaging target including at least one primaryimage object and at least one secondary image object. The electronicdevice also includes an image-processing chain arranged in connectionwith the camera means for processing the image data formed from theimaging target, and a focussing means for focussing the camera means onat least one primary image object. Blurring means are arranged in theimage-processing chain, to blur at least some of the said secondaryimage objects in the image data, which blurring means are arranged touse the information produced by the focussing means.

According to another embodiment of the invention, disclosed is a methodin digital imaging for processing image data, in which method camerameans are used to form image data from an imaging target, the imagingtarget including at least one primary image object and at least onesecondary image object. The camera means are focussed on at least oneprimary image object, and the camera means are used to form focussedimage data, which image data is processed in the device, in order toachieve the desired changes in the image data. In the processing, atleast some of the said secondary image objects in the image data areblurred using the information produced in the focussing.

In addition, the invention also relates to a corresponding programproduct and a focussing module to be fitted for use in the device. Thus,according to an embodiment of the invention, disclosed is a programproduct for processing image data in an electronic device, which programproduct forms of a storage medium and program code written on thestorage medium to be executed using a processor means. The electronicdevice includes camera means for forming image data from an imagingtarget, the imaging target including at least one primary image objectand at least one secondary image object, an image-processing chainarranged in connection with the camera means, for processing the imagedata formed from the imaging target, and focussing means for focussingthe camera means on at least one primary image object. The program codeincludes first code means configured to blur at least some of the saidsecondary image objects in the image data, using the informationproduced by the focussing means.

According to another embodiment of the invention, disclosed is afocussing module, which can be arranged in an electronic device forperforming imaging. The device includes camera means for forming imagedata from an imaging target, the imaging target including at least oneprimary image object and at least one secondary image object, animage-processing chain arranged in connection with the camera means, forprocessing, in the device, the image data formed from the imagingtarget, and in which the focussing module can be arranged in the deviceat least for focussing the camera means on at least one primary imageobject. In addition, blurring means are arranged in the image-processingchain to blur at least some of the secondary image objects in the imagedata, which blurring means are arranged to use the information producedby the focussing module.

The invention is particularly suitable for application, for example, insuch digital cameras, in which there is wide depth of field. Suchcameras are known, for example, from mobile stations. The invention canbe applied in both still and video imaging.

In the invention, the information obtained from focussing of the camerais applied. The one or more image objects in the image in whichsharpness is to be retained, and correspondingly the image objects to beblurred, can be decided on the basis of this information. Focussinginformation is available immediately in the imaging situation, so thatits application takes place very smoothly for achieving the purposes ofthe invention.

The blurring of inessential image objects can be performed, for example,by using filtering. There can even be precalculated filteringcoefficients in the device for filtering, from which the most suitablegroup of coefficients can be selected for use in each situation. On theother hand, the statistics formed for focussing can be used to calculatethe filtering coefficients.

In the invention, the end user can create a blurring effect in the imagesurprisingly already in the imaging stage using the camera. Thus, thereis no need at all for a separate post-editing operations that would takeplace outside the device after the imaging event.

One of the advantages achieved by the invention is that using smallcameras, which generally are precisely those with wide depth of field,an such image can be achieved, in which the primary image object issharp and the background, or the secondary image objects in general, areblurred or otherwise made unclear.

The other characteristic features of the invention will become apparentfrom the accompanying Claims while additional advantages achieved areitemized in the description portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, which is not restricted to the embodiments described inthe following, is examined in greater detail with reference to theaccompanying figures, in which

FIG. 1 shows an example in principle of an application of the electronicdevice according to the invention, as a schematic diagram,

FIG. 2 shows an example of an application of the program productaccording to the invention, for implementing blurring in an electronicdevice in the manner according to the invention,

FIG. 3 shows an example in principle of the method according to theinvention, as a flow diagram, and

FIG. 4 shows an example of an imaging target, to which the invention isapplied.

DETAILED DESCRIPTION

FIG. 1 shows an example in principle of an application of the electronicdevice 10 according to the invention, as a flow diagram, on the basis ofwhich the invention is described in the following. In addition, FIG. 2shows an example of the program product 30 according to the invention.The program product 30 forms of a storage medium MEM and program code 31stored on it, with reference to the code means 31.1-31.5 belonging towhich program code 31 being made at suitable points in the followingdescription, to connect them to the method and device 10 according tothe invention.

The device 10 can be, for example, a digital camera equipped with astill and/or video imaging capability, a digital video camera, a mobilestation equipped with a camera, or some other similar smart communicator(PDA), the components of which that are inessential from the point ofview of the invention are not described in greater detail in thisconnection. The invention relates not only to the device 10, but equallyto an imaging-chain system 27 and a focussing module 28, such as may be,for example, in the device 10. One example of such a focussing module 28is the Ai-AF system developed by Canon.

The device 10 according to the invention, and with it also the imagingsystem can include, as modular components, camera means 11, 14 and adigital image-processing chain 27 connected to it and a focussingcircuit 28.

The camera means 11, 14 can include an image sensor totality 12, 13,which is as such known, together with movable lenses 15, by means ofwhich image data ID of the imaging target IT can be formed. The imagingtarget IT, which is converted by the camera sensor 12 in a known mannerto form electrical signals, is converted into a digital form using an ADconverter 13.

The focal length of the camera means 11, 14 may be less than 35 mmdeclared as a focal length equivalency with 35 mm film. Some examples ofthe focal lengths of the camera means may be, declared as a focal lengthequivalency with 35 mm film, for example, 15-20 mm (special wide-angle),20-28 mm (wide-angle) or 28-35 mm (mild wide-angle). The use of theinvention achieves a particular advantage in devices 10 with anextensive depth of field, but the invention can of course also beapplied in such devices with a narrow depth of field (for example,teleobjectives).

The focussing means 28 are in the device 10 for focussing the camerameans 11, 14. A solution that is, for example, as such, known, or whichis still under development, can be applied as a focussing circuit 28.Using the focussing circuit 28, at least one of the image objects I1, I2in the imaging target IT can be focussed to the camera means 11, 14,more particularly to the sensor 12, prior to the performance of theimaging that it intended to be stored, or even during imaging to bestored, if the question is of, for example, a video imaging application.This is because the imaging target IT can include at least one primaryimage object I1, relative to which it is wished to focus the camerameans 11, 14, and at least one secondary image object I2, which is animage subject that is of less interest from the point of view of theimaging. It can be, for example, the background to the primary imageobject I1.

In cameras, focussing conventionally involves the collection ofstatistics from the image data ID. According to one embodiment, thestatistics can include, for example, a search for gradients for thedetection of the edge of the primary image object I1. The statistics canbe formed of, for example, luminance information of the image data ID.The focussing operations also include the movement of the lenses 15, inorder to maximize the statistical image sharpness mathematically bycomparing statistical information. Focussing can be performedautomatically or also by the end user, who can manually adjust thefocus, if there is, for example, a manually adjustable focus disc(mechanical focus control) in the camera.

If the focussing is implemented automatically in the device 10, thefocussing circuit 28 shown in FIG. 1 can include an as such knownautofocus control algorithm 24, in which there can be a focuss-pointdefinition portion 24 as a sub-module. As input, the algorithm portion24 receives AutoFocus AF-data from the calculating module 23 of AFstatistics. The statistics module 23 can process the image data IDcoming directly from the AD converter 13, in ways that are, as such,known, and form from it, for example, the aforementioned gradient data.On the basis of the data produced by the statistics module 23, thealgorithm portion 24 can decide whether it images the selected firstimage object I1 sharply to the sensor 12 in the set manner. As output,the algorithm portion 24 produces control data that is as such known,for the adjustment mechanism 14 of the set of lenses 15. The controldata is used to move the set of lenses 15, in such a way that the one ormore image objects I1 defined as primary by the focus-point sub-module25 is imaged precisely and sharply to the sensor 12.

The image-processing chain 27 connected to the camera means 11, 14 caninclude various modules in different implementation arrangements, whichare used, for example, for processing, in the device 10, the image dataID formed from the imaging target IT. In both cases, whether imaging tobe stored is being performed at that moment by the device 10 or not, itis possible to perform so-called viewfinder imaging, for which there canbe a dedicated module VF in the device 10. The viewfinder VF can beafter colour-interpolation 16, or also after the blurring filter 17according to the invention, which will be described in greater detail alittle later. In that case, the blurred background can, according to theinvention, already be seen in the viewfinder image.

The image-processing chain IC can consist of one or more processingcircuits/DSPs 16, 18, which are, in terms of the invention, entirelyirrelevant components, and no further description of them is necessaryin this connection. In this case, the colour-interpolation 16 andimage-data ID compression 18 of the image-processing chain 27 are shown.When the image data ID is stored, this can take place to some storagemedium 19. The technical implementation of these components, which areirrelevant in terms of the invention, will be obvious to one versed inthe art and for this reason the invention is described in thisconnection at a very rough block-diagram level, for reasons of clarity.In terms of the practical implementation of the invention, hardware andsoftware solutions, as well as combinations of them, can be considered.Of course, some of the operations of the modules 16, 18, 23, 24, 25belonging to he image-processing and/or focussing chain 27, 28 can beimplemented even in a single module.

As a surprisingly module, blurring means 17, 22, 26, forming a blurringmodule 21, are arranged in the image-processing chain 27. Of course, thesub-modules 17, 22, 26 belonging to the module 21 can also provide othertasks in the device 10 than those belonging to blurring, as will bedemonstrated later (for example, focussing). The means 17, 22, 26 can beused in a surprising manner to blur at least part of the secondary imageobjects I2 in the image data ID, which are not the primary object ofinterest in the imaging target IT, which the sensor 12 detects in itsentirety.

In the embodiment of FIG. 1, only the filtering module 17 of theblurring means is shown itself in the actual chain 27. The other modulesthat implement blurring in the embodiment in question are thefiltering-coefficient calculation module 22 and the focussed-areacalculation/definition module 26.

In order to blur the image objects I2 that are set to be secondary, theblurring means 17, 22, 26 use the information produced by thefocussing-module totality 28. The focussing-area calculation module 26can use the data obtained from the AF-statistics calculation portion 23in the definition of the image area I1 and now also the data obtainedfrom the focussing point definition portion 25. Once the portion 26 hasbeen calculated the focussed, i.e. the primary image object in the imagedata ID, its location in the image information formed by the image dataID, can be determined and also its shape, i.e. the location areas of theone or more primary image objects I1 in the image IT.

The data obtained from the calculation portion 26 of the focussed areacan be sent to the filtering coefficient calculation module 22. On thebasis of the data of the focussed focus area, i.e. in other words of theportrait area, the final area, which is used in the calculation of thefiltering coefficients, can be selected/calculated. This area can evenbe pixel-accurate, thus delimiting the primary image object I1 veryprecisely. On the other hand, the portrait area used can be entered, forinstance manually, for example, by lassoing from a touch screen, if thedevice has one. The module 22 can calculate the filtering coefficients,by using which the secondary image objects, i.e. the areas I2 areblurred. The filtering coefficients calculated by the module 22 areprovided to the filtering module 17, which performs the blurring of theirrelevant image areas I2. This will be returned to in greater detail inthe description of the method given next.

FIG. 3 shows a flow chart of a schematic example in principle of themethod according to the invention in digital imaging for blurringinessential image areas I2. In the method description, reference is madeto an example of an imaging situation, which is shown in FIG. 4. In it,the image target IT consists of two people, a man with a briefcase and awoman reading a newspaper, as well as a short length of rolled-steeljoist. In this case, the people are the primary image objects I1 whilethe length of joist is the secondary image object I2, which it is wishedto blur. In general, the background area of the entire image area can,in connection with the invention, be understood as being such asecondary image object I2.

When imaging is started with the device 10, the imaging program isactivated, as stage 300, which in this case applied automatic focussing.In stage 301, the set of lenses 15 can be adjusted using the mechanism14 to the initial focussing position.

As stage 302, image data ID is formed using the sensor 12, i.e.viewfinder shots are formed, for example, for the viewfinder VF. Inpractice, the formation of the image data ID is performed continuously,the frequency being, for example, 15-30 frames per second. In stages 303and 304, focussing operations that are, as such, known, can beperformed. As such, all the blocks 301-304, which are inside the blockwith a broken line around it, can be understood to be focussingsub-stages.

The actual focussing stages 303 and 304 can be taken care ofautomatically by the focussing module 28, or allowance can also be madein them for operations made by the user. When focussing is carried outmanually by the end user, the user can freely select the primary imageobjects I1 or image object areas FA, to be focussed, from the viewfinderVF. This automatic or manual selection also affects the objects to beblurred. In stage 303, the user can, for example, from the image data IDformed by the sensor 12 for the viewfinder VF, to define at least one oreven more image objects I1, on which it is wished to focus the camerameans 11, 14. The selection made by the user can include, for example,the lassoing of an area, in which case even irregular objects can be setas primary image objects I1. On the other hand, the primary image objectI1 can also be fitted to a predefined area with a rectangular or othershape. Several different kinds of areas can be predefined in the memoryMEM of the device 10.

In the automatic focussing/image-object selection application, focussingcan be concentrated on, for example, one or more image areas (forexample, on the centre of the imaging object). The focussing points canalso be intelligently selected from the entire image area. One exampleof this is Canon's Ai-AF system (Artificial intelligence AF).

In stage 304, by the module 28, more particularly, for example, itssub-module 24, can be determined whether the image object I1 has beenfocussed properly.

If it is determined, in stage 304, that the focussing is not correct,the automation 24 calculates new positions for the set of lenses 15.After that, a return is made to stage 301, in which the set of lenses 15is moved to the new calculated positions. If, however, it is determinedin stage 304 that the focussing is correct, the procedure moves to theactual imaging for storing, i.e. to stage 305.

In stage 305, imaging for storing is performed, when the trigger buttonof the camera 10 can be pressed all the way down. The image data IDcaptured using the sensor 12 is taken from the module 13, which performsthe AD conversion, to the image-processing chain 27. In theimage-processing chain 27, colour interpolation, using module 16, forexample, can be performed as stage 306. Other stages will also beobvious to one versed in the art and neither they, nor their order ofperformance are described here in greater detail.

Besides specific one or more image objects I1 being able to be focussedin the previous stages 303 and 304 in a manner that is, as such, known,this focussed image area I1, or more particularly its position, size,and/or shape can also be used to blur the undesired image objects andtheir areas I2, in stage 307. For this purpose, there are code means31.1 in the program code 31. In stage 303, the focussing point can beused to indicate one or more objects, i.e. in the context of theinvention, a primary image object I1 inside the imaging target IT.Around the selected focussing point, for example, the edges and shapesof the image object I1 can be identified, for example, in order todetermine the size of the image object I1 and the position of thefocussing point. In other words, this refers to the determining of thesize of the primary image object I1. This can be carried out by applyingthe statistical information from stages 303 and 304, more generallyproduced by the focussing operation 28 obtained from the focussing stageindicated by the broken line. As a result of the operation, thesecondary image objects I2 are, of course, also defined, these beingdefined by the code means 31.5.

Once the information concerning the position and size of the focussedprimary area I1 of the imaging target IT has been obtained, variousfiltering operations, for example, can be performed on the image, bymeans of which the background, i.e. the secondary image objects I2 areblurred, or made less sharp, as desired. The code means 31.2 achievesthis operation. The filtering can be of, for example, an evening type,such as spatial low-pass filtering. According to one embodiment, in theinvention spatial filtering coefficients, for example, can be calculatedusing the module 22 (code means 31.3). The filtering coefficients canforms, for example, a mask that convolutes the image, which can be usedto process the inessential image areas I2.

The convoluting mask, or in general the filtering coefficients can bedefined, for example, from the luminance data formed by the focussingportion 28, and even more particularly from the luminance data thatrefers to the secondary areas I2 that are to be blurred. One criterionfor the definition of the coefficients of the mask can then be, forexample, that the blurring should be made to create “an even grey”, thusavoiding the creation of a background that becomes too dark or toolight. As is known, as a result of convolution, the pixel values thatare greater or less than the extremes of the luminance scale aregenerally cut to the extremes of the scale (for example, to zero, or tothe value 255, if the depth is 8-bit). In order to avoid this kind ofcutting to the extremes, the coefficients of the convoluting mask areattempted to be made to be adapted, using the focussing data, to be suchthat cutting of this kind does not occur. According to a secondembodiment, blurring can also be made in such a way that noise isstrongly mixed with the background area, or the secondary areas I2 ingeneral, after which the background (i.e. noise) is low-pass filtered tobecome even. This too can be handled by the code 31.2. When applyingcoefficients in the filtering, the focussed area I1 is made to remainuntouched, i.e. sharp. In part, this is caused in such a way that theareas of the primary image objects I1 are not processed at all, but onlythe inessential areas I2 are processed. Correspondingly, as a result ofthe coefficients, the sharpness of the areas I1 remaining outside of thefocussing area, i.e. the secondary areas in the context of theinvention, is then reduced.

On the other hand, suitable groups of filtering coefficients groups,i.e. masks, using which filtering is then performed, can also beprearranged in the device 10. Stated in more general terms, the device10 can provide filtering coefficients, either by calculating them on thefly, or by providing them from a “coefficient bank” prearranged in thememory MEM.

Even more particularly, an area can also be taken into account, forexample, in stage 303, in such a way that the edge and/or shapeinformation of the primary image object I1 can be applied to select anon-rectangular shape. In the device 10 there can also be differentkinds of precalculated area shapes. An attempt can be made to apply themto the selected primary image object and then select/use the one thatfits best. As some examples of these may be mention rectangular,circular, elliptical, and triangular areas FA. Among other things, theuse of precalculated areas FA brings an advantage in the use of theprocessing power of the device 10, because, in the case of area shapesthat are frequently repeated, there is no need to perform thecalculation again. There are code means 31.4 in the program code 31, forperforming this operation.

The result, after the operations according to the invention, is animage, which are limited depth of focus. As final stages 308-310, theimage data ID is compressed and stored on the desired medium 19.

FIG. 2 shows a rough schematic diagram of one example of a programproduct 30 according to the invention. The program product 30 caninclude a storage medium MEN and program code 31, written on the storagemedium MEM, to be executed using the processor means CPU of the device10, for implementing blurring according to the method of the inventionat least partly on a software level. The storage medium MEM of theprogram code 31 can be, for example, a static or dynamic applicationmemory in the device 10, or a blurring-circuit module totality being inthe imaging chain IC, with which it can be directly integrated.

The program code 31 can include several code means 31.1-31.5 to beexecuted by the processor means, the operation of which can be apply inthe method descriptions given immediately above. The code means31.1-31.5 can consist of a group of processor commands to be performedconsecutively, by means of which the functionalities desired, in termsof the invention, are created in the device 10 according to theinvention.

Owing to the invention, a background blurring effect can be implementedin small digital cameras too, surprisingly already in the imaging stage,without any need for difficult post-processing. One example of an areaof application of the invention can be the blurring of the background inportraits. In portrait applications may be additionally applied facerecognition on basis of which the focus area and the background area tobe blurred may be calculated. For the recognition may be used the colorof the face which can usually be easily recognized by the algorithmsknown as such. The case-specific calculation of filtering coefficientswill achieve the most suitable background/blurring for each imagingtarget IT.

Though the invention is largely described above as a still-imagingapplication, it can, of course, also be applied video imaging, as wellas to viewfinder imaging performed before the imaging for storing. Invideo imaging, it should be understood that the flow chart of FIG. 3will then form a continuous loop, in which imaging, focussing, andblurring can be performed as a continuous process (from block 305 theprocedure also moves to block 302). In any event, the imaging forstoring is performed whether the focussing is then optimal or not (instage 304, the procedure moves in the directions of the yes and noarrows). The focussing is iterated automatically to become correct byadjusting the optics 14, without, however, interrupting imaging.

It must be understood that the above description and the related figuresare only intended to illustrate the present invention. The invention isthus in no way restricted to only the embodiments disclosed or stated inthe Claims, but many different variations and adaptations of theinvention, which are possible within the scope on the inventive ideadefined in the accompanying Claims, will be obvious to one versed in theart.

The invention claimed is:
 1. A digital camera comprising: a cameracomponent configured to form image data from an imaging target includingat least one primary image object and at least one secondary imageobject, the camera component comprising an analog to digital converterconfigured to convert the imaging target to image data animage-processing chain arranged in connection with the camera component,configured to process the image data formed from the imaging target, anda focussing circuit configured to focus the camera component on at leastone primary image object, a processing unit configured to define morethan one primary image object in the image data and to define theremaining parts of the imaging target as the at least one secondaryimage object, a blurring filter configured in the image-processingchain, to blur at least the defined at least one secondary image objectin the image data, which blurring filter is configured to use thedefining of the at least one secondary image object, wherein theblurring is arranged to be performed in an imaging stage before imagingfor storing, and a viewfinder module configured to provide a viewfinderimage comprising the at least one blurred secondary image object in theimaging stage before imaging for storing.
 2. A digital camera accordingto claim 1, wherein the focal length equivalency with 35 mm film of thecamera component is less than or equal to 35 mm.
 3. A digital cameraaccording to claim 1, wherein the blurring filter is configured toperform the blurring by filtering the image data.
 4. A digital cameraaccording to claim 1, wherein the digital camera is configured to storefiltering coefficients, such as, spatial filtering coefficients, and theblurring filter is configured to use the filtering coefficients onperforming the blurring.
 5. A digital camera according to claim 1,wherein the processing unit is configured to fit the more than oneprimary image objects to an area with a set shape, wherein a collectionof shape defining coefficients corresponding to these areas isprearranged in the digital camera.
 6. A digital camera according toclaim 1, wherein the blurring filter is configured to perform theblurring in connection with the formation of the image data.
 7. Adigital camera according to claim 1, wherein the blurring filter isconfigured to blur the secondary image objects by applying noise to theareas corresponding to them, which area is then configured to beequalized by low-pass filtering.
 8. A method comprising: using a cameracomponent to form image data from an imaging target, the imaging targetincluding at least one primary image object and at least one secondaryimage object, and the camera component comprising an analog to digitalconverter configured to convert the imaging target to image data,focussing the camera component on at least one primary image object, andusing the camera component to form focussed image data, which image datais processed in a digital camera, in order to achieve the desiredchanges in the image data, the method further comprising: defining morethan one primary image object in the image data and defining theremaining parts of the imaging target as the at least one secondaryimage object, and in the processing, blurring the defined at least onesecondary image object in the image data using the defining of the atleast one secondary image object, wherein the blurring is arranged to beperformed in an imaging stage before imaging for storing, and providinga viewfinder image comprising the at least one blurred secondary imageobject in the imaging stage before imaging for storing.
 9. A methodaccording to claim 8, wherein the defining of the more than one primaryimage object is based on information produced in the focussing.
 10. Amethod according to claim 8, wherein the blurring is performed byfiltering the image data.
 11. A method according to claim 8, whereinfiltering coefficients are calculated from the information produced inthe focussing, using which the blurring is performed.
 12. A methodaccording to claim 8, wherein the more than one primary image objectsare fitted to an area with a set shape, the areas outside of which areaare blurred.
 13. A method according to claim 8, wherein the blurring isperformed in connection with the formation of the image data.
 14. Amethod according to claim 8, wherein the secondary image objects areblurred by configuring noise in the areas corresponding to them, whicharea is then low-pass filtered to equalize it.
 15. A computer programstored in a storage medium to be executed by a digital camera, thedigital camera including: a camera component configured to form imagedata from an imaging target, the imaging target including at least oneprimary image object and at least one secondary image object, and thecamera component comprising an analog to digital converter configured toconvert the imaging target to image data, an image-processing chainarranged in connection with the camera component, configured to processthe image data formed from the imaging target, and a focussing circuitconfigured to focus the camera component on at least one primary imageobject, wherein the computer program comprises a computer executableprogram code configured to cause the digital camera to when executed bythe digital camera to: define more than one primary image object in theimage data and define the remaining parts of the imaging target as theat least one secondary image object, blur the more than one secondaryimage object in the image data, using the defining of the at least onesecondary image object, wherein the blurring is arranged to be performedin an imaging stage before imaging for storing, and provide a viewfinderimage comprising the at least one blurred secondary image object in theimaging stage before imaging for storing.
 16. A computer programaccording to claim 15, wherein the computer code is further configuredto cause the blurring by filtering.
 17. A computer program according toclaim 15, wherein the program code is further configured to cause thedigital camera to calculate filtering coefficients from the informationproduced by the focussing circuit, and to perform the blurring using thefiltering coefficients.
 18. A computer program according to claim 15,wherein the program code is further configured to cause the digitalcamera to fit the more than one primary image object to an area with aset shape, a collection of filtering coefficients corresponding to whichareas being prearranged in the digital camera.
 19. A computer programaccording to claim 15, wherein the program code is configured to beexecuted in connection with the formation of the image data.
 20. Acomputer program according to claim 15, wherein the program code isfurther configured to cause the apparatus to define the said secondaryimage objects to be blurred, by using said information produced by thefocussing circuit.
 21. A computer program according to claim 15, whereinthe defining of the more than one primary image object is based oninformation produced in the focussing.